How about password-protected paper mail?

How about password-protected paper mail?

Technology News |
By eeNews Europe

This password-protected envelope is one of three demonstrators developed during the four-year ROPAS (ROll-to-roll PAper Sensors) European project involving 11 partners from research and industry.

Other demonstrators included a security tag to be used for sending physical goods through traditional mail and enabling recipients to check that the box was not opened during transport and that the good is in its genuine package, and a smart label able to measure and record environmental parameters such as humidity and temperature during transport to display them on a display at the push of a button.

All tags bear in common printed conductive inks for tamper-detection circuitry (opening the package or envelope tears down the contacts and triggers the open status), a small printed battery from partner Enfucell, some printed sensor switches and a form of display (printed OLEDs for the envelope and the smart tags, a flexible display for the smart label.)

For the purpose of the demonstration, the envelope embedded a printed antenna and advanced logic optimised for a 300m communication range with dedicated base stations placed at different logistic points.

"Although for the demonstration, we used a proprietary antenna design, we could well integrate NFC circuitry so the recipient could confirm reception using a regular NFC-enabled phone", told us Liisa Hakola, Senior Scientist from VTT.

"Typical use cases for such password-protected envelopes would include the mailing of credit cards or ID documents such as passports or driving licenses. First the recipient would be informed, possibly by email that he or she is about to receive the password-protected document, the unique password would be communicated at that time. Then, upon receiving the envelope, the recipient can power-up the envelope (one press of a button) and enter his/her password using the five-digit sensor switches", explained Hakola.

The smart envelope with password protection features sensor buttons (1-5), an electronic inlay for RF communication with the base station, Enfucell batteries, and written instructions for user guidance.


Each press of a button is confirmed visually with a LED blink, and this password entry triggers the envelope to send out an acknowledgement to the sender, either via the postman’s portable base station or using an NFC-enabled smartphone to communicate with the sender’s cloud infrastructure.

If on the contrary the envelope was tampered with or opened prior to having entered the correct password, it would send out an alert for the sender to take action (for example disabling the credit cards or the electronic passport). The smart envelope also requires an antenna to cover large distances and advanced logic to enable wireless communication.

Slightly less complex, the security tags should turn on a green LED light when the recipient presses a button, but if the package has been tampered with (the label tracks cut open), then a white LED highlights a tamper icon instead.

VTT labs claim these new paper tags would be more environmentally friendly than their plastic-substrate based equivalent, highlighting that the components used in the security element have a minor influence on the optical and mechanical properties of recycled fibres.

"The use of conductive printing inks is so minimal that their impact is almost negligible," Hakola pointed out.

Now the consortium is looking for someone to adopt the technology in the logistics or the retail sectors. The ROPAS project was coordinated by TNO from the Netherlands, and the other research partners in addition to VTT were ITENE from Spain and CEA from France. The companies involved included S2Grupo and Longinser from Spain, Starcke and Enfucell from Finland, MpicoSys from Poland, Océ from the Netherlands, and ELEP from Belgium.

More about the ROPAS consortium at

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